A liquid crystal display, compared with current main stream display, i.e., CRT (Cathode Ray Tube), has merits in that it can be manufactured very thin and light. With technical advances in wide viewing angle and motion picture, its applications have been expanded as well.
In recent years, liquid crystal displays have been used extensively for desk top personal computer monitors, monitors mainly for use in printing or designing, and liquid crystal display televisions. With this trend, liquid crystal displays are now faced with new demands such as improved color purity of red, green and blue and superior color reproduction for halftone colors like the color of a person's face. Moreover, liquid crystal displays are required to provide high contrast ratio, expanded dynamic range, and color reproduction covering from high brightness to low brightness.
Conventional liquid crystal displays, however, have a problem that their color tones are easily changed due to changes in brightness (or tones). In case of liquid crystal display televisions, high brightness is particularly a very important attribute required.
To realize high-brightness liquid crystal displays, Japanese Patent Laid-Open No. 2004-4822 discloses a liquid crystal display panel which has a white pixel in addition to the conventional RGB (Red, Green and Blue) pixels in one pixel unit.